The present invention relates to a sorter which is provided to an image forming apparatus such as a copier and printer to sort sheets discharged from the apparatus, and more particularly relates to a sorter having a plurality of bins, and the sorter is provided with a stapling device to arrange and staple the sheets in the bin.
For a sheet processing device provided with a stapling device to staple sheets discharged from a copier, printer and the like, a sheet finisher has been utilized which is installed together with an automatic recirculating document handler in order to staple the sheets. However, the aforementioned sheet finisher is disadvantageous because the structure is so complicated and expensive.
(1) In Japanese Patent Publication Open to Public Inspection no. 43457/1989, has been disclosed an apparatus in which a stapling device is provided to a relatively simple bin-moving type of sorter. In the aforementioned apparatus, a stapling device to staple sheets sorted into a bin can be freely moved with regard to the bin.
(2) Another sorter is composed in such a manner that: a fixed type of stapling device is provided to each bin; and the bin is moved to the stapling position so that a bundle of sheets can be stapled.
(3) A sorter disclosed in the official gazette of Japanese Patent Publication Open to Public Inspection No. 244869/1987, is composed in such a manner that: a bin having sheets is moved to a position where a stapling operation can be conducted; the sheets are stapled by a stapling device; and when the sheets in other bins are stapled, the stapling device is moved in a vertical direction.
In the aforementioned sorter of case (1) having a stapling device which can be moved freely, the moving stroke of the stapling device is different according to sheet size. Accordingly, when the vertical spacing of each bin is set large, the sorter size becomes large as a whole, and when the vertical spacing of a bin into which the stapling device is inserted, is extended, the mechanism becomes complicated.
In the aforementioned sorter of case (2), the structure of the sorter is complicated as a whole, and in the case where the vertical spacing of the bin is small, a special stapling device is required.
In the aforementioned sorter of case (3), each bin in which sheets are put, is moved straight along a bin guide at an appropriate time. Accordingly, it is disadvantageous in that the structure becomes complicated.
When various sizes of sheets are discharged from an image forming apparatus in such a manner that the center of the sheets coincides with the center of a bin, and when the sheets in the bin are aligned in such a manner that the sides of the sheets are bumped against a reference face, an alignment rod or plate of an alignment unit must be moved by a long distance. Therefore, the sides of the sheets conveyed into the bin at high speed can not be aligned accurately, so that the sides of the sheets can not be aligned accurately.
Sheets not aligned accurately are disadvantageous when a stapling or punching operation is conducted after the sheets have been sorted.
Further, the present invention relates to a sorter provided with a stapling device which staples the sheets in a bin in such a manner that a shifting frame in which a plurality of bins are disposed, is moved in a direction perpendicular to the sheet conveyance direction.
As sorter systems which automatically sort a plurality of sheets (copy sheets) discharged from an image forming apparatus such as a copier, there are a fixed bin system, an all bin shifting system, and a bin opening movement system.
In the case of the fixed bin system, a plurality of copies are made from a plurality of documents by an image forming apparatus in such a manner that: the sheets conveyed from the image forming apparatus are successively received by a receiving section of a sorter; then the sheets are moved to a conveyance section; as shown in FIG. 1, while the sheets are being conveyed, they are successively taken into bins 41 by a sorting guide 36 and a delivery roller 35 which are installed in the receiving portion of the bin 41.
The aforementioned bin fixed system is advantageous in that: a relatively large number of sheets can be put into the bin: the sorter can respond at a high speed; and a plurality of sorters can be connected. Therefore, this type of sorter is frequently applied to a console type of high speed copier. For example, 50 sheets can be stacked in each of the bins for sorting use, and 250 sheets can be stacked on a tray for non-sorting use.
In the driving means to move the aforementioned frame, there are various plays such as play between a worm directly connected with a motor shaft and a worm wheel, play between the gears of a plurality of gear trains, and play caused by a backlash between a pinion and pinion gear. When these plays are accumulated, play of several millimeters is finally caused. Therefore, a problem is caused in which the stop position of the frame is fluctuated, so that the positions of sheets put in the frame are varied and the stapling positions are remarkably fluctuated.
Further, the present invention relates to a sorter which sorts the sheets discharged from an image forming apparatus in such a manner that the bins are moved from a waiting position to a position corresponding to the sheet size.
A conventional type of sorter will be described as follows.
FIG. 28 shows an outline of sorter B which is connected with the outside of a delivery roller 101 of copier A. When a sort mode is set in sorter B, a route from a passage 103 to a passage 104 is formed by changing over a gate 102. A copied transfer paper (which will be referred to as a paper, hereinafter) discharged by the discharge roller 101, is conveyed upwardly by a conveyance belt 106 of an upward conveyance section 105. When the papers are selectively changed over by a plurality of gates 107, they are discharged into a plurality of bins 109 of a bin shift unit 108 one by one in such a manner that: the first paper is discharged into the uppermost bin, the second paper is discharged into the next bin, and the papers are discharged into the downward bins successively. After a predetermined number of papers have been put into the plurality of bins 109, a paper aligning operation, which will be described later, is conducted. After that, paper bundles in the bins 109 are stapled by a stapling device 110.
FIG. 29 is schematic illustrations which explain the motion of the bin shift unit 108. Before the motion of copier A starts, this bin shift unit 108 is located in a predetermined waiting position (a home position). According to the size of the paper 111 discharged from copier A, the bin shift unit 108 is moved in the direction shown by an arrow D in FIG. 29. In the aforementioned case, the size is defined as a size in the direction perpendicular to discharging direction C, and for example, this size is detected in the process of paper feeding of copier A, and the detected data is sent to sorter B. In the above explanation, the direction indicated by arrow D is a direction vertical to the surface of FIG. 28. As a result, the paper 111 is discharged into the bin 109 in such a manner that one side edge of the paper 111 is positioned close to a side stopper 112 on the side of a stapler 110 in the bin 109. Since the bin 109 is inclined upwardly, the paper 111 discharged onto the bin 109 slips back by its dead weight so that the trailing edge of the paper 111 bumps against a trailing edge stopper 113 to be aligned.
After the last paper 111 has been discharged onto the last bin 109, an alignment rod 115 which is common in all bins and located in a cut-out portion 114 of the bin 109, is moved in the direction of arrow E by the rotation of an arm 116, so that a bundle of the papers 111 on the bin 109 are pushed toward the side stopper 112. As a result, the bundle of the papers 111 are aligned to be stapled appropriately.
After that, as indicated in FIG. 30, stapling operations are conducted on the bundles of the papers 111 from the uppermost bin 109 successively. The tip of an arm 118 rotated by the torque generated by a bin rotating motor 117, is engaged with an engaging portion 119 of the bin 109, and the bin 109 is rotated around a shaft 120 which is common in all bins. In the manner described above, a cut-out edge 121 of the bin 109 is moved to a position of the stapler 110 referred to as a stapling position. Then, the edge of the bundle of the papers 111 is stapled by the stapler 110. After that, the bin rotating motor 117 is reversed, so that the bin 109 is returned to the original position. After all the bundles on the bins 109 have been stapled, the alignment rod 115 is returned to the original position and the bundles of the papers 111 can be taken out from the bins 109.